Since the early days of SCUBA (Self Contained Underwater Breathing Apparatus) diving with Jacque Cousteau, communication between SCUBA divers has been an issue. This is due to the fact that: i) the use of the SCUBA breathing apparatus (including a mouthpiece worn by the diver precludes direct voice communication, and ii) because of risks of the underwater environment, divers have a critical need to communicate a variety of safety related messages to their fellow divers, e.g., communicating the amount of air they have remaining (a maxim of diving is to never dive alone, but instead always go with at least one other diver known as a “dive buddy”). As a result, a series of hand signs have been developed but these only cover a very limited number of messages and cannot quickly get the other diver's attention in critical situations. Various underwater graphical display devices have also been developed, but these have the same limitation. These devices which are worn on the diver's wrist or arm require the diver to divert his or her attention from what they are doing to look at the display. Typically, divers dive with their head up to see where they are going and their arms at their sides to reduce water resistance. So, the diver's natural diving position is not conducive to monitoring a visual alert on their wrist or elsewhere (e.g., arm or waist). This is even true for visual alerts on the diver's face mask since the diver's attention is more focused on what is in front of them and not their face mask.
Acoustic alarm systems have been developed but they are not voice based and can only communicate a limited number of messages which require the diver to understand an alarm code. Also, none of these devices provide for communication between divers and a surface craft such as the dive boat (the boat which supports the divers). Further none of these devices provides for communication between divers who are not in very close proximity. What is needed is an approach allowing for voice communication between divers while they are underwater as well as for voice communication between divers and a surface craft.